Apparatus for perforating sheet material



July 31, 1945. G. F. WALES 2,380,485

` APPARATUS FOR PERFORATING SIHEET MATERIAL Filed March 18, 194:5 3Sheets-sheet 1 l WM 7o h j (ATTORNEYS G F WALES APPARATUS -FORPERFORATING SHEET MATERIAL Filed'March 18, 1945 y 3 Sheets-Sheet 2 O ,28I i 3 Sheets-Sheet 3- INVENTOR my? ATToR YS Filed March 18, 1945Patented July 3l, 1945 I George Wales, Kenmore, N. Application Mitch 18,1943, Serial N0. 479,815

(ci. isi-s4) 34 Claims.

This invention relates to an apparatus for plmching holes at specifiedlocations throughout the areas of sheets of material such as sheet thenumerous rivet holes required in the thin metal panels or sheets whichare used in aircraft construction to liorm the outer surfaces of wings,i'uselages, and the like. but the invention may be applied to other useswhere relatively large numbers of holes are required in panels or sheetsof.

materials.

The main object of my invention is to provide an apparatus and methodfor punching holes in metal, and is particularly adapted for punchingsheet materials which is simple in construction,

economical to manufacture and use. and easily set up for use in a press.

Another object is to provide a multiple hole punching apparatus and amethodvof making same in which the punch carrier plate may be used as adrill iig for drilling the die plate when both plates are assembledtothe other parts yof the apparatus in the same manner in which they areto be used in the punching operation. l

Another object is to provide such an apparatus for the successiveaccommodation of any number of pairs of punch and die carrier plates.thus requiring the preparation only of the plates when new patterns ofholes are to be punched.

A further object is to provide an apparatus of this nature in whichso-cal1ed non-critical materials may be used for the majority of partsespecially the punch carrier plates, the base plates and the Ysupportmembers.

Another object of this invention is to provide A -ing a multiple holepunching die whereby they punching devices are interchangeable from onepunch carrier plate to another and also with Another object is toprovide a die plate foran apparatus of this nature which is made of ametal capable of being hardened, and hardened around the die openings.

A further object is to provide anapparatus of this description in whichthe punches may be instantly serviced bylifting them freely out of theirguideways in the punch carrier plates to prevent lossof time when apunch fails.

These and other objects and the several novel h features of thisinvention are hereinafter more fully described and claimed and thepreferred form of construction by which these objects are obtained. isshown in the accompanying drawings in which:

Fig. 1 is a front elevation showing a prefer-re design of my apparatusmounted on the stationary bed or bolster of a press and showing thereciprocating ram in its lowermost position in which the punches aredriven through the work.

Fig. 2 is a plan view of the apparatus shown in Fig. 1. l

Fig. 3 is a fragmentary horizontal section taken on line 3 3, Fig. 2,showing the ram in a partially elevated position, and showing locatingpins for correctly positioning the punch plate and die plate relativelyto each other.

Fig. 4 is a fragmentary horizontal section similar to Fig. 3, butshowing how the holes are drilled in the die plate preparatory to theilnal assembly of the apparatus.

Fig. 5 shows an alternate method of drilling the punchand die platestogether.

Fig. 6 shows how the punch plate holes are enlarged to accommodate thepunch and punch guide elements.

Fig. 7 shows the die plate as it was drilled in '.Fig. 5 and being llamehardened before being drill bushings which are substituted for them whendrilling a die plate by using each punch can-ier pme as a drm Jig fordrimng the die apertures in coaxial alignment in its companion dieplate. t

Another object is to provide an apparatus and method for punching. amultiplicity of holes in either in'tllcdl'llllnscri-immuun:open-ations.i tin.

placed in service.

F18. 8 is a fragmentaryv sectional view d the punching mechanism in anoperating position, and showing a punch unit of modiiled construction.

Fig. 9 is a fragmentary section showing a modiiied construction in whichone of the rails is connected with the base by a bolt passing throughthe rail and having its head arranged in a T- shaped or undercut slot,which latter extends crosswise of the base, and thus permits therail tobe shiftedcrosswise to permit of using die plates and punch plates ofdifferent widths.

Fig. 10 is a plan view similar to Fig. 2, but Showing BtOD me means ofmouiiled construcstandard punch press or similar machine which includes,among other elements, a lower supporting bed which forms the lower partof the stationary main frame of the press and on which is usuallymounted a bolster plate and an upper ram which is guided upon the upperpart of this main frame and movable vertically toward and from said bed.

In the space between the bolster and ram of the press. the perforatingapparatus embodying my improvements is arranged and adapted to beoperated by the movement of the ram toward the bed for the purpose ofpunching holes in the sheets of material which are fed to theperforating' mechanism.

The diierent features of my improved perforating mechanism may bevariously constructed and still embody the underlying principle of theinvention.

The preferred organization of my invention which is shown in thedrawings is constructed as follows:

The numeral I represents .the stationary bed or bolster of a press andII the reciprocating ram ofthe press. The numeral I8, Figs. l to 4,represents a base plate resting loosely on the bed or bolster I0 of thepress and I2 represents two supports having the form of bars or railswhich are mounted in spaced relation on transversely opposite parts ofthe base plate and secured thereto by bolts 23 passing through flangeson the outer sides of these rails, as shown in Figs. l, 2, 3 and 4. Ontheir inner sides the two supports or'rails are rabbeted to formupwardly facing shoulders,

shelves or ledges I4 on which the transversely opposite edges of a dieplate I3 rest and to which these parts of the die plate are secured bymeans of cap screws I5. Between the rails I2 the die plate I3 may besupported by brace pins I5, which may be attached to the plate I3 bymeans of a threaded or otherwise prepared shank I1 at the upper end ofthis pin secured in an opening in the die plate, as shown in Figs. 1 and3, said pin be used t0 support die plate I3, or any other being of thesame length as the height of the means which provides support for thedie plate while at the s ame time making provision for slugs punchedou't from the work-piece to be cleared from underneath the die plate.Each of the -brace bars I8 has its lower edge resting on the base plateI8 and-may be secured thereto by screws 46 or the like and has its upperedge cut away or recessed on a downwardly tapering angle rectly upon thebolster plate Il of a press, they are for the most part attached to amounting or -base plate I8, to provide a unitary assemblage which may befully prepared for operation outside of the press and merely slid ontothe bolster plate I0 where it is ready for immediate operation. As thesupports or rails I2 may be used for different widths and lengths of dieplates, such as I3, and punchplates. such as 24, the base plate I3 maybe small or large to suit the size of plates I3 and 24. It might beadvisable also to employ in place of plate I8 a base plate IBI, Fig. 9having T-slots running crosswise of this plate, as indicated by 25 inFig. 9, in which case bolt heads 23| would extend into said slots 25 andnuts used fclirtcelamping the supports or rails I2 to said base pa Eachof the supports or rails I2 is provided with an upper bearing surface 25upon which is mounted one edge portion of a punch carrier plate 24,which carries vertically moving tubular punch guides 21, each of whichis guided in holes 28 bored in this plate and held in an elevatedposition by light springs 28. 'I'he guide sleeves 21 are provided withvertical holes extending clear through for the-accommodation of puncheseach of which consists of Punch body 3| and punch head 32 at the upperend of the body.

In order to strip the work-piece 38 from the punch, resilient means areinterposed between the underside of each punch head and the upper faceof the respective guide sleeve, which means may take the form of helicalsprings, truncoconical washers, rubber, or any other means, such asrubber washers 33, and metal washers 34, alternating as shown in Fig. 8.Take-up washers 3|) are inserted between the lowermost rubber washer andthe top of the respective guide tube or sleeve 3| when thel punch is newand these takeup Washers may be removed as the punch wears and is groundshorter and thus prevent over-compressing the rubber washers.

Preferably the punch unit 'is constructed so I that the height of thevarious punch units may be the same. This may be accomplished by havingthe upper end of the punch extend through its head 32 and providing acap 300 with a central aperture into which the upper end of the punchmay extend, as shown in Fig. 8. The cap also has a downwardly extendingannular skirt portion 30| extending about the head. As the punch becomesshorter by grinding the lower end thereof, any washer 30 removed fromits place above the upper end of the punch guide sleeve may be placedupon the head 32of the punch and below the cap 300, thus keeping thetotal distance from the plate 24 to the upper end of the cap the same.

first on one side of the bar, as shown at 20, and` then on the otherside thereof, as indicated by 2|, thus staggering or alternating theserecesses and providing a top surface 22 having an effective areasuilcient to adequately `support the die plate I3, whileat the same timeproviding slug chutes or recesses which enables the bars to support thedie plate when holes are punched close together, and provides means forthe slugs from such holes to clear the lower ends of the die apertures.

While supports or-rails I2 may be mounted diregardless of the length ofthe punch.

'I'he punch plate 24 is attached to supports or rails I2 by means ofbolts 35, and this plate is proyvided with openings 36 to provide accessto bolts I5, which attach the die plate to the ledge of the supports I2below the level of the punch plate.

The organization by which this apparatus provides Vthe simplicity ofpreparing the punch plate and die plate will be discussed later. Forthepresent, let it be assumed that the plates have been prepared by formingthe holes 28 in the punch plate (Fig. 6) for the punching elements incorrect relation to each other as desired in the finished part. Alsothat the holes 42 for the bilis 35 have been drilled so that said punchplate may be bolted to the supports I2. Also let Ait be ar- `upon thebase plate or in any other manner. fbeen formed and properly preparedto--slidably III for bolts Il have been formed in the die plate. Thenthe manner of assembling the apparatus is asfollows: r v

If brace pins I3 are used they are engaged with die plate I3 whereverrequired. If brace bars I3 are used, they are placed in position on baseplate I3. The supports or rails I2 are then placed I3 in the approximateposition to accommodate die plate I3 which is placed on. the ledges I4.By shifting the die plate and rail, one relative to the other, thescrews I will iind tapped holes in the rails and may be tightened andthis will clamp the die plate I3 in position where it will be resting onthe brace bars Y I3, or pins I3. Punch plate 24 is then placed on thesupports I2 and screws 35.

The holes in the die plate clamped by meansof the n, through which boltsIl extend, are enough larger than the body` of the bolt to provide easyassembly ofthe plate with the supports I2. The holes for bolts 35 inpunch plate 24 are larger than the body of the bolt to allow the punchplate '24 to be shifted slightly to obtain proper concentric alignmentof the die holes 31 with the punch guide holes 23 before being clampedtightly. `'ll'his alignment is obtained by inserting locating pins 45 inthe punching device holes 23' of the punch plate as substitutes forpreferably*` three punching devices. These pins are reduced at theirlower ends to form pilots 46| which Just flt the respective die openings31 in such manner that the two plates I3 and 24 may be positioned withall companion holes in concentric relation with one another. The twoplates I3 and -24 are then both bolted tightly to the supports I2.Screws I5, being socket head cap-screws, are tightened by inserting awrench through the openings 36.. The locating pins 45 are then removedand the punching devices reinstated, upon which the apparatus is readyto operate.

.It is taken for granted that gaging means must l be used to locate thework 3|! properly in the apparatus and pins 33, ora nest, may be used onthe die plate for this purpose.

Another method of gazing the work properly is illustrated in Fig. 10,according to which holes 40| are formed in the work-piece, previous tothe present operation and pilot pins 40 vare provided von the upperfaces of the brace bars. These brace bars I9 are then adjusted so thatpilot pins 40 on these bars engage the holes in-the workpiece when thispiece is in correct relation to the punch and die units, in which casepins 33, or the nest, are not used. When pins 40 are used, the bracebars are anchored against movement by screws 46 in plate I3. Obviouslythe locating pins maybe arranged in the die plate I3, if desired. s

I have shown work-piece 33 projecting in front of the apparatus. 1f,however, the work enters entirely into the apparatus, it may bedesirable punch plate and the bolts 33 and this plate is then clampedtightly in place on supports I2 which are bolted to the base plate I3.

A blank die plate Il of chrome-molybdenum steel, or other steel capableof being flame hardened, is then drilled to take the bolts Il, and thisblank plate I3 is then slid onto ledges I4 and the bolts insertedthrough holes 33 in the tightened by means of a socket wrench engagingthe socket head screws I5. Y

The next step which is novel in die construction consists of inserting adrill bushing 43 in one of the punch plate openings, inserting a drill5| in the hole of this bushing, and drilling the die hole 31, as shownin Fig. 4. The size of the drill is such as to give the proper clearancebetween the punch and the die hole. All punching operations require thatthe die hole be larger4 than the punch by from 5% to 25% of thethicknessv of the material. The hole`44 in the drilll bushing willtherefore be the size of the required die hole and not the punch size.As an example, if the punch is .125 in diameter and the metal to bepunched .050 thick, the drill size will be 10% of .050 larger, or .130in diameter. When drilling die plate I3 by this means, the support orbrace bars I3 may be shifted around to provide positive support 4for thedie plate. After one hole has been drilled, the drill bushing 43 isvremoved and placed in another hole 23 of the punch plate and theprocedure repeated until all of the die holes are formed in the dieplate. These die holes will then be in perfect alignment with the punchholes in punch carrier plate 24, and the portion of the plate aboutthese holes can be hardened 'without removing the plates l from theirsupports by inserting a burner through the holes in the punch plate.

The die plate I3 may also be hardened` by a name 60' around the dieholes (Fig. '1) by removimmediate; vicinity of the hole 31, to avoidwarping of the plate I3, a ring 3i of flre clay or other material may bearranged about the vhole while the part Within the ring is heated. Ofcourse, tliie plate may be removed for hardening if des red.

By extending the brace bars I9 forward as at 50 in Fig. 2 a feedingledge is provided on which the work-piece may be placed before insertingit into the apparatus.

If desired, the punch plate and die plate may be held together by boltsIBI similar to the bolt I5 and while thus connected a die hole 31 maybebored therein and a companion preliminary hole 31| may be formed in.the punch plate in alignment with the hole 31 by a drill 5I. Thereafterthe plates I3 and 24 are separated and each of the preliminary holes 31|is enlarged to receive to out out hand openings or notches like 4I to lenable the operator to place the piece in position properly. Sight holes4|0 may be provided in the punch plate 24 through which the gage pins 33may be easily seen. v y The preparation of the punch carrierplate 24consists of first drilling and reaming the holes 23, wherever a hole isdesired in the nnished piece. The holes may be located from templatesAfter these holes have receive sleeves or tubes 21, the holes 42 aredrilled in the punch plate larger than the diameter of distance fromeachother and when a job is finished, the punch and die plates can -beremoved from the supports which can thenbe used for 'another set ofpunch and die plates. Since thesa except the drilling and reaming ofIthe holes, and they are, consequently, easily and economically made.

The method and apparatus described may be used in any case where arelatively large number of holes are required in a sheet of material,but are particularly desirable for many uses in airplane constructionwhere it has been considered impractical to punch holes in platesbecause of the relatively high cost and time required to make thenecessary hole punching dies. My improved apparatus can. however, beproduced at a cost not more than the cost of drill Jig-plates nowcommonly used for stack drilling .the work, and

once the apparatus is made, the work can be don'e at a rate of from tento fifty times faster than drilling. economy in the use of drills, whichare replaced in my apparatus by the use of punches oi' simple andinexpensive construction.

With .the construction shown, a single set of plates may be providedwith two or more series of holes for two or more different jobs,providing that the holes are so located ln the two sets of plates thatthey do not overlap or interfere'with each other. For example, there aretwo series of holes in the plates shown in Fig. 2, one series for use onthe work-piece 38. The-punch units are shown positioned in these holes.The same plates maybe provided with additional holes 85 for use onanother job. When theflrst :lob is being done, punch units are placedonly into the holes of one series and whenthe second job is to be doneby means of the same apparatus, all the punch and die units are removedfrom the first series of holes and are placed in the holes 85. This mayrequire the use of other stopgages for positioning the work. In thismanner, a number of different types of work can be-pro duced by means ofa single apparatus.

I claim as my invention:

My apparatus also eilects a further l. A sheet material perforatingapparatus comprising a base, spaced supports resting onsaid base, a dieplate mounted on said supports in spaced relation to said base andprovided with die openings, a punch plate mounted on said supports inspaced relation to said die plate and provided with guide openings inline with said die openings, guiding and stripping Itubes arranged vinsaid guide openings, punches slidable in said tubes and adapted tocooperate with said die openings, resilient means for raising said tubes'relative to said punch plate, and resilient means for raising saidpunches relative to said tubes.

2. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted on said supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said die plate andprovided with guide openings in line with said die openings, guiding andstripping tubes arranged in said guide openings, punches slidable invsaid tubes and adapted to cooperate with said die openings, resilientmeans for raising said tubes relative to said punch plate, resilientmeans two plates are flat, they require no machining.

die openings, a punch plate mounted on said supports .in spaced relationto said die plate, punches slidable on said punch plate and adapted tocooperate with said die openings, vresilient means for'stripping saidpunches from the work, and bracing means interposed between said dieplate and said base including a bar engaging its upper edge with theunderside of said die plate and its lower` edgewith the upper side ofsaid base and provided on its upper edge with recesses adapted toreceive slugs from said die openings and discharge Ithem laterally,

4. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted on said supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said diev plate,punches slidable on said punch plate and adapted to cooperate with saiddie openings, resilient means for stripping said punches from the work,and bracing means interposed between said die plate and said baseincluding a bar engaging its upper edge with the underside of said dieplate and its lower edge with the upper side of said base and providedon its upper edge with recesses adapted to receive slugs from said dieopenings and discharge them laterally, said recesses being arranged instaggered relation 'on opposite sides of said bar.

5. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted on` said supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said die plate,punches slidable on said punch plate and adapted to cooperate with saiddie openings, resilient means for stripping said punches from the work,

and bracing means interposed between said die plate and said baseincluding a bar engaging its upper edge-with the underside of said dieplate and its lower edge with the upper side of said base and providedon its upper edge with recesses adapted to receive slugs from said dieopenings and discharge them laterally, said recesses being arranged instaggered relation on opposite sides of said bar and each of saidrecesses having an inner inclined deflecting surface.

6. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted on said supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said die plate andprovided with guide openings in line with said l`die openings, guidingand stripping tubes arfor raising said punches relative to said'tubes,

and bracing means interposed between said die plate and said base.

3. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a dieplate mounted on said supports inspaced relation to said base and provided with ranged in said guideopenings, punches' slidable in said tubes and adapted to cooperate withsaid die openings, resilient means for raising said tubes relative tosaid punch plate, resilient means for raising said punches relative tosaid tubes, and means for locating the work-piece to be perforated onthe die plate.

"7. A sheet material perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted on said supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said die plate,punches slidable on said punch plate and adapted to cooperate with saiddie openings, resilient means for stripping-said punches from the work.and

'5 means for locating the work-piece to be perforated on the die plateincluding a brace bar secured to the base and engaging the underside ofthe die plate and provided with a locating pin ranged in said guideopenings, punches slidable J in said tubes and adapted to cooperate withsaid die openings, resilient means for raising said tubes relative tosaid punch plate, resilient means for raising said punches relative tosaid tubes, and means for locating the punch plate relative to the dieplate. L

9. A sheet material perforating apparatus comprising a base,spaced'supports resting on said of said rails and provided with dieopenings, a punch plate having its opposite edge portions secured to theupper surfaces of said rails and Drovided with guide openings in linewith said die openings, punching units arranged in said guide openingsand cooperating with said die openings, Iand screws securing said dieplate to said shoulders and accessible through openings in said punchplate. l

13. A sheet perforating apparatus comprising a die plate having dieopenings, a punch plate arranged above the die plate and provided .withguide openings in line with the die openings, and

punching units each including a guiding yand stripping sleeve slidablein one oi said guide openings and adapted to` engage its lower end withthe top of the work-piece, means to allow the sleeve to slide and toraise it again. a punch slidable in said sleeve and adapted to cooperatewith one of said die openings, and resilient means for raising saidpunch interposed between the upper base, a die plate mounted on saidsupports in spaced relation to said base and provided with die openings,a punch plate mounted on said supports in spaced relation to said dieplate and provided with guide openings in line with said die openings,guiding and stripping tubes arranged in said guide openings, punchesslidable vin said tubes and adapted to cooperate with said die openings,resilient means for raising said tubes relative to said punch plate,resilient meansv for raising said punches relative to saidtubes, andmeans for locating the punch plate relative to the die plate including aplurality of locating pins adapted to be inserted into some of saidguide openings and engaged at their ends with some of said die openings.

l0. A sheet vmaterial perforating apparatus comprising a base, spacedsupports resting on said base, a die plate mounted onlsaid supports inspaced relation to said base and provided with die openings, a punchplate mounted on said supports in spaced relation to said die plate andprovided with guide openings in line with said die openings, guiding andstripping tubes =arranged in said guide openings, punches 'slidable insaid tubes and adapted to cooperate with said die openings, resilientmeans for raising said tubes relative-to said punch plate, resilientmeans for end of said sleeve and a shoulder on said punch and includinga plurality of alternating metal washers and rubber disks through whichthe punch passes.

14. An apparatus for punching a plurality of holes in sheets of materialcomprising a punch carrier plate provided with holes in accordance withwhich a counterpart is to be punched, punching units in said holes, anda die plate provided with apertures to cooperate with said punch units,said die plate being mounted in iixed spaced relation below said punchcarrier plate in such manner that work placed between said plates willbe n v punched when said punching units are properly actuated towardsaid die plate.

15. An apparatus for. punching a plurality of holes in sheets ofmaterial comprising a punch carrier plate provided with holes inaccordance with which a counterpart is to be punched, punchtion belowsaid punch carrier plate in such manner that work placed between saidplates will be punched when said punching units are properly actuatedtoward said die plate, said die plate being supported in spaced relationto the bed of the w press.

raising said punches relative to said tubes, and

means for locating the punch plate relative to the die plate including aplurality of locating pins adapted to be inserted into some of saidguide openings and having reduced tips engaging some of said dieopenings.

11. A sheet metal perforating apparatus comprising a base plate, spacedsupporting rails secured thereon, each rail having a supporting. surfaceon its top side and a rabbet on its inner side forming an intermediateupwardly facing shoulder, a die plat'e having its opposite edge portionssecured to the shoulders of said rails and provided with integral dieopenings, a punch plate having its opposite edge portions secured to thetop surfaces of said rails and provided with guide openings in line withsaid die openings, and

.punching units arranged in Ysaid guide openings and cooperating withsaid' die openings.

1'2. A sheet metal perforating apparatus comarabbet on its inner sideforming an intermediate upwardly 'facing shoulder, a die plate havingits I0 prising a base plate, spaced supporting rails each v -16. Anapparatus for punching a plurality of holes in sheets of materialcomprising a. punch carrier plate provided with holes in accordance withwhich a counterpart is to 'be punched, punching units in said holes, anda die plate provided with apertures to cooperate with said punch units,said die plate being'mounted in xed spaced relation below said punchcarrier plate in such manner that work placed between said plates willbe punched when said punching units are properly actuated toward saiddie plate, said die plate being supported in spacedrelation to the bedof the press and being braced at intervals from the bed of the press bysupports spaced clear of said die holes.

17. An apparatus according to `claim 15 in which the die plate has onlythatportion oi' the plate in. 'the immediate vicinity of each holehardened.

18. An apparatus according to claim 15 in which the portions of theholes below the upper face of said plate are enlarged to facilitate theremoval of slugs punched out of the work and in ,n which only thatportion of the plate4 in the immediate vicinity of each hole .ishardened.

opposite edge portions secured to the shoulders 19. Perioratingapparatus, including a pair of flat plates spaced apart and held in xedrelation to each other and having holes therein, punch units slidablymounted in the holes of one of said plates, the die holes in the otherplate being of such size as to cooperate with punches .oi' said punchunits, each hole of one of said plates being in axial alinement with ahole of the other plate, whereby the punch units may move toward andinto said holes in said plate to perforate the work positioned thereon.

20. A perforating apparatus, including a pair of fiat plates spacedapart and held in xed relation to each other and having holes therein,punch units slidably arranged in the holes of the upper of said plates,the holes in the lower of said plates being of a size to act as dies incooperation with said punch units, each hole of one of said plates beingin axial alinement with a hole in the other plate, whereby punches maybe moved relatively to their plate into hole-punching relation to theother plate.

21. A sheet material perforating apparatus comprising spaced supportsformed to rest upon the bed of a press, a die plate mounted on saidsupports in spaced relation to the lower ends thereof and provided withdie Aholes in the plate itself, a punch carrier plate secured on saidsupports in fixed spaced relation to` said base and having guideopenings in alinement with the die openings of the die plate, individualpunching and stripping units slidably mounted in the guide openings insaid punch plate, whereby when work to be perforated is placed upon saiddie plate, the punches of said punching and stripping units willcooperate with the die holes to perforate the work.

22. A sheet material perforating apparatus, including a pair ofplatesprovided with holes therein arranged according to the pattern of holesdesired in the work, each hole of one plate being in axial alinementwith a hole of the other plate, supports cooperating with the edgeportions of said plates for supporting said plates, one above the other,in ilxed spaced relation to each other,

individual'punching and stripping units slidably arranged in the holesof the upper plate, means for sliding said punch units upwardly topermit work to be placed between said plates and being slidabledownwardly to perforate the work, the holes in thelower plate beingformed to cooperate with the punch of said punching units forperforating the work.

23'. A sheet metal perforating apparatus, comy tioned'pl'ate and havingholes therein, each hole being in axial alinement with a hole in thelower plate, punch units mounted `lin the holes of the uppergplateland'including-punches adapted to penetrate: work pla'cedn' said lower plateand en ter into the die holes of the lower plate, said punches beingof"a size to fit the holes in said diepia-te itse1f. y

24;' A'punch unit for use in a perforating de viceMSaid punch-unitincluding a punch guide n sleeve, a punchslidable lengthwise of saidsleeve,

a head for 'saidpunchfav resilient stripper .mem-

ber between said head and said sleeve, said punch unit includingalternately arranged rubber disks and rigid washers, for withdrawing thepunch out of the work and into said sleeve, and means for supportingsome of said washers above said head when said punch becomes shortened.

25. A punch unit for use in a perforating device, said punch unitincluding a punch guide sleeve, a punch slidable lengthwise of saidsleeve, a head for said punch, a resilient stripper member between saidhead and said sleeve, said punch unit including alternately arrangedrubber disks and rigid washers, for withdrawing the punch out of thework and-into said sleeve, a portion of said punch extending through andabove said l head, and a cap on the upper end of said punch and having ahole to receive said poi ion of said punch, whereby a rigidwasher may beremoved from below said head to above said head and between said headand said washer to compensate for reduction in length of said punch.

26. A punch unit for use in a perforating device, said punch unitincluding a punch guide sleeve, a punch slidable lengthwise of saidsleeve, a head for said punch, a resilient stripper member between saidhead and said sleeve, said punch unit including alternately arrangedrubber disks and rigid washers, for withdrawing the punch out of thework and into said sleeve, a cap for said punch fitting over the headthereof and having a skirt portion into which said head may telescope,whereby when the punch becomes. shortened, washers may be removed frombelow said head and placed between said head and said cap, to

lower said punch in said sleeve and maintain the same Overall length ofsaid punch unit;

27. A perforating apparatus for use in a press, including supportsformed to receive a punch unit carrier plate and a die plate secured iniixed spaced relation to each other, said punch carrier plate havingholes therein arranged according to the pattern of holes required in thework, punch units arranged in said holes, said die plate having holesarranged therein so that each hole of one plate is in axial alinementwith a hole of the other plate, and means for releasably. securing saidplates to said supports, so that said plates may be removed from saidsupports and replaced by other plates for operating on work of adifferent kind, said supports with said plates mounted thereon beinginsertable into and removable from a press without changing thepositions of said plates relatively to each other.

28. A perforating apparatus according to claim 27, and including a baseplate connecting said supports and spaced below said punch carrier plateand said die plate.

29. A perforating apparatus, according to claim 27 and including aT-slotted base plate on which said supports are removably mounted and onwhich said supports are adjustable toward and from each other tocooperate with plates of different widths.

30,'A perforating apparatus, including a pair of ilat plates `spacedapart and held in xed relation to each other and having -holes therein,punch units slidably arranged in the holes of the uppery of said plates,the holes in the lower of said plates being of a size to act as dies incooperationv with said punch units, each hole of one of saidplates beingin axial alinement with a hole in theotherplate, whereby punches maybe'moved relatively to their plate into hole-punching relation. to theother plate, and stop gages for the c work on the lower of said plates.

31. A perforating apparatus, including la pair of flat plates spacedapart and held in iixed relation to each other and having .holestherein, punch units slidably arranged in th holes of the upper of saidplates, the holes in the lower of said plates being of a size toact asdies in cooperation with said punch units, each hole ofone of saidplates being in axial alinement with a hole inthe other plate, wherebypunches may be moved relatively to their plate into hole-punchingrelation to the other plate, stop gages for the work on the lower ofsaid plates, and a sight hole in the upper plate through which astopgage can be seen to facilitate positioning the work in correctrelation to the stop gage.

32. A perforating apparatus including a punch carrier plate having aplurality of series of holes ferent types of work -by placing punchunits into diierent series of holes in said punch unit supporting plate.

33. An apparatus for punching a multiplicity of holes in sheet materialincluding spaced plates xed to end supports andy carrying a multiplicityo f slidable punches in concentric relation Yabove cooperating Vdieelements in the lower plate and means for varying the lengths of saidpunch elements for maintaining the over-all length of each punchapproximately the same as every other punch.

34. A punch unitfor use in a perforating device, said punch unitincluding a punchguide sleeve, a

4punch slidable lengthwise of said sleeve, resilient stripper means forretaining said punch in an elevated position relative to said sleeve forwithdrawing the punch out of the work and into said sleeve, and meansfor varying the length of said punch unit for maintaining the overalllength of said punch unit to compensate for unequal lengths of otherpunches in a group due to reductions in length which occur in servicing.

' GEORGE F, WALES.

same apparatus may be used for producing dif'

